Researchers at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have developed a process that enables 3D printed parts to change color after printing. The method, called ColorMod, relies on specialized and UV-responsive 3D printable inks.
MIT’s CSAIL researchers have been responsible for some pretty amazing advances in additive manufacturing, including a software system capable of generating 3D printable microstructures that meet certain desired properties, and 3D printed hydraulic robots capable of walking off the print bed.
The lab’s latest achievement is nothing short of amazing, as it enables users to 3D print color-changing objects.
Similar in concept to 4D printed objects—which change shape post-printing when exposed to certain elements—prints made using the ColorMod process are not in their final form when they are removed from the build plate.
Using their specialized UV-responsive bioinks, the researchers were able to fully recolor a 3D printed plastic object in just over 20 minutes. As the research advances, they hope to quicken the process.
But how exactly does it work? Well, according to the CSAIL team, it simply uploads a 3D model into its ColorMod software which allows it to choose a color pattern for the object. Once the object is printed in full color, the team exposes it (or parts of it) to UV light or visible light.
The parts of the 3D printed object hit with UV light become colored, while the parts exposed to visible light (such as a projector light) lose their color and become transparent. These reactions are due to a special light-responsive ink made from a base dye, a photoinitiator (that hardens the ink during printing), and light-adaptable dyes (which bring out the base dye’s color).
Samples of the color-changing inks
The researchers hope that their ColorMod technology will be adapted beyond 3D printed plastic with the eventual goal of applying it to textiles and clothing.
“Largely speaking, people are consuming a lot more now than 20 years ago, and they’re creating a lot of waste,” commented Stefanie Mueller, the X-Consortium Career Development Assistant Professor in the departments of Electrical Engineering and Computer Science and Mechanical Engineering. “By changing an object’s color, you don’t have to create a whole new object every time.”
Mueller, who appeared on our Women’s Day post celebrating influential females in the 3D printing industry, co-authored the ColorMod paper along with postdoc Parinya Punpongsanon, undergraduate student Xin Wen, and researcher David Kim.
One specific application of the technology would be to 3D print accessories which could be matched and customized depending on what the user is wearing. CSAIL has also suggested that retail shops could use the technology to customize products on the spot. Wishing that belt came in blue not green? ColorMod could be the answer!
“This is the first 3D printable photochromic system that has a complete printing and recoloring process that’s relatively easy for users,” added Punpongsanon. “It’s a big step for 3D printing to be able to dynamically update the printed object after fabrication in a cost-effective manner.”
ColorMod was previously called ColorFab, which was perhaps too close to the name of Dutch filament company colorFabb